INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2012
·
IF 2.237
Rulong Li,Huabin Xing,Qiwei Yang,Xu Zhao,Baogen Su,Zongbi Bao,Yiwen Yang,Qilong Ren
This paper presents an extensive study on the feasibility of ionic liquids (ILs) for the extractive separation of a 1-hexene/n-hexane mixture. Seventeen ILs were tested at 313 K. The extraction selectivities of 1-hexene to n-hexane were in the range 1.5–3.0. The chemical structures of anion and cation in ILs greatly affected the extraction, and the functional groups, such as carbon–carbon double bond, nitrile, ester, and amide, in the ILs led to higher selectivities. The increase of alkyl chain length in cation led to the increase of extraction capacity of 1-hexene. To increase the distribution of 1-hexene in IL phase, silver salt was added to the ILs. It was found that ILs containing silver salt had a high distribution of 1-hexene, as well as high selectivity of 1-hexene against n-hexane. The extraction efficiency increased with the concentration of silver salt in ILs. When the initial feed concentration of 1-hexene was smaller, the selectivity of 1-hexene to n-hexane was higher. A simple mathematical model has been developed to describe the total 1-hexene content in the reaction media under study, on the basis of the formation of complexes between silver and 1-hexene with different stoichiometry. This work proves that the ILs can act as effective extractants in 1-hexene/n-hexane separation.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2021
·
IF 6.609
Tao Pan,Sida Ge,Mengnan Yu,Yana Ju,Ran Zhang,Pei Wu,Kuanyu Zhou,Zhijie Wu
Zn modified ZSM-5 zeolite supported Ni bifunctional catalysts were prepared by in-situ hydrothermal synthesis (Zn-Ni-ZSM-5), co-impregnation method (Zn-Ni/ZSM-5) as well as combining in-situ hydrothermal synthesis of Zn-ZSM-5 and sequential impregnation of Ni (Ni/Zn-ZSM-5) and used for the selective converting olefin to aromatics applicable for FCC gasoline hydro-upgrading. The Lewis (L) acid sites generated by ZnOH + species and hydrogenation active sites from Ni 0 species were varied with preparation method, in which their locations at the external surface or micropores of zeolite changed the acid properties of catalysts. Comparing to the Zn-Ni/ZSM-5 from the co-impregnation method, direct in-situ hydrothermal method could incorporate Zn and Ni species within zeolite, which makes the strong interaction between the metal species and the framework Al to form medium-strong L acids (ZnOH + /NiOH + ). This leads to the decrease of ratio of Brønsted acid sites to L acid sites (B/L) from 0.40 to 0.12 and the difficulty in reducing of Ni cations to Ni 0 from 57% to 30% Ni 0 percent. Ni/Zn-ZSM-5 sample prepared by incorporating Zn species into micropores and sequential depositing Ni species at the external surface of zeolite possesses a low B/L ratio similar to Zn-Ni-ZSM-5 (0.20 versus 0.12) but a much higher Ni 0 percent (52% versus 30%). Zn-Ni-ZSM-5 shows closer intimacy between Zn and Ni species comparing to Zn-Ni/ZSM-5 and Ni/Zn-ZSM-5. For the 1-hexene aromatization, the formed iso -alkene at acid sites was quickly saturated to iso -alkanes by the adjacent Ni 0 particles over Ni-Zn-ZSM-5 catalyst in hydrogen steam. However, the location of aromatization active sites (ZnOH + , L acid sites) in micropores and hydrogenation active sites (Ni 0 species) on external surface of Ni/Zn-ZSM-5 makes the tandem conversion of n-alkene → iso -alkene → aromatics, rather than the n-alkene → iso -alkene → iso -alkane. Thus, Zn-Ni-ZSM-5 with close intimacy of ZnOH + and Ni 0 particles shows a high iso -alkane selectivity (27.9% iC 4 + ), while Ni/Zn-ZSM-5 exhibits a high aromatics selectivity (39.6 %) in the conversion of 1-hexene in hydrogen steam. Similar results have also found in the conversion of n-heptane. Here, the control of the intimacy of Zn and Ni in ZSM-5 zeolites has been realized to be a good protocol to adjust the selective conversion of olefins/alkanes to aromatics versus iso -alkanes.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2024
·
IF 3.9
Yuhao Yang,Minghui Tan,Hailun Geng,Xiujuan Gao,Yisheng Tan,Qingde Zhang
Oriented designing the microenvironment of catalytic sites is essential for understanding catalytic processes. In this work, EDTA was first grafted in UiO-66 and then chelated Rh to obtain an efficient catalyst for 1-hexene hydroformylation reaction. EDTA not only served as a chelation site for Rh immobilization in UiO-66, but also markedly influenced the structure and properties of Rh/UiO-66. The incorporation of EDTA reduced the micropore content and suppressed the formation of heavy products. Moreover, the grafted EDTA regulated the electronic state of Rh effectively to improve the CO and propene adsorption, thus constructing an appropriate microenvironment for hydroformylation. Therefore, EDTA-modified Rh/U-E catalyst exhibited higher aldehydes yield, TOF and stability than Rh/U without EDTA. The dual role of EDTA in anchoring Rh sites and modulating the microenvironment for hydroformylation provides more prospects for designing customized MOFs-based catalysts.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2022
·Vol. 12
·期 22
·6827-6837
·
IF 6.177
Penghui Li,Junhua Gao,Jing Shi,Huixiang Wang,Xiangying Xing,Jingzhao Ren,Yu Meng,Liancheng Wang,Baoliang Lv
Linear terminal olefin epoxidation is a significant oxidation reaction for the synthesis of valuable industrial intermediates. As typical olefin epoxidation catalysts, supported tungsten oxides are rich in oxygen vacancies, which have been investigated for improving catalytic performance in other reactions, but the influence on olefin epoxidation is rarely studied. Herein, a series of WO3−x/SBA-15 catalysts with different oxygen vacancy concentrations were obtained by impregnation and sequent hydrogen reduction at 300–600 °C. Their catalytic performances for 1-hexene epoxidation with hydrogen peroxide at 70 °C were studied. It was found that an appropriate concentration of oxygen vacancies could improve epoxidation (the epoxide productivity increased from 135 to 196 μmolepoxide gW−1 min−1) and reduce the apparent activation energy (from 51.6 to 46.9 kJ mol−1). The oxygen vacancies are also beneficial for cycloolefin and other linear olefin epoxidation. In particular, the productivity of cyclooctene oxide was promoted from 4161 to 5744 μmolepoxide gW−1 min−1. This promotion effect was attributed to the increase in the number of Lewis acid sites caused by introducing moderate oxygen vacancies, which could improve the activation of hydrogen peroxide and facilitate epoxidation. In situ FT-IR spectroscopy and density functional theory calculations further indicated that increasing the oxygen vacancies contributes to reducing the energy barrier of the transfer of electrophilic oxygen atoms in active intermediate W–OOH to 1-hexene, thereby promoting epoxidation.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2018
·Vol. 8
·期 63
·36298-36312
·
IF 2.936
Xiaohui He,Guangshui Tu,Feng Zhang,Shengmei Huang,Changwen Cheng,Chuanyi Zhu,Yapeng Duan,Suli Wang,Defu Chen
Eight bis-(salicylaldehyde-benzhydrylimino)nickel complexes with different electron groups (Ni1–Ni8), Ni{(3-R1)(5-R2)C6H2(O)CHNCH(C6H5)2}2, (R1 = H, R2 = H, Ni1; R1 = H, R2 = CH3, Ni2; R1 = H, R2 = OCH3, Ni3; R1 = H, R2 = Br, Ni4; R1 = CH3, R2 = H, Ni5; R1 = OCH3, R2 = H, Ni6; R1 = Br, R2 = Br, Ni7; R1 = Cl, R2 = Cl, Ni8), were synthesized and their crystal structures were characterized using single crystal X-ray diffraction. The results revealed that Ni1–Ni6 belong to the monoclinic system (space group P2(1)/n), Ni7 belongs to the monoclinic system (space group C2/c) and Ni8 belongs to the triclinic system (space group P). All nickel complexes exhibited high activities (0.46–2.07 × 106 gpolymer molNi−1 h−1) toward norbornene homopolymerization, and a strong electron-withdrawing group on the salicylaldimino aromatic ring can enhance the catalytic activity and favor polymerization. Ni1 and Ni2 exhibited high activities (0.55–2.40 × 105 gpolymer molNi−1 h−1) toward copolymerization of norbornene and 1-hexene in the presence of B(C6F5)3. The 1-hexene content in the copolymers could be controlled up to 7.98–12.50% by varying the comonomer feed ratio of 1-hexene from 10 to 50%. It is observed that when the 5-position of the salicylaldimino aromatic ring has a substituent (–CH3), the 1-hexene insertion rate is lower than that without a substituent. In addition, the polymers showed high molecular weights (1.5–2.4 × 105 g mol−1) and narrow molecular weight distributions (1.62–1.89). The obtained polymers were also verified to be amorphous copolymers and had high thermal stability, good solubility and optical transparency.
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Science-Advanced Materials and Devices
·
2022
·
IF 7.382
Xiaoyan Xue,Yan Sun,Qiwen Sun,Weiren Bao,Zongsen Zhang,Liping Chang,Jiancheng Wang,Kechang Xie
As an atom economy technology, the direct esterification reaction of olefins plays a significant role in the production of organic esters. In this work, a series of resin-supported HPW catalysts were prepared using D101, D152, RM027, and A15 as the carriers, and they were used to prepare 1-methylpentyl acetate by the esterification of 1-hexene and acetic acid. The composition, structure, morphology, acid content, and other parameters of catalysts were characterized. In the esterification reaction, the activity order of catalysts is as follows: 20.0%HPW/A15 > 20.0%HPW/D101 ≈ 20.0%HPW/D152 > 20.0%HPW/RM027. It depends on the acid strength of the carrier, the interaction between the carrier and HPW, and the HPW content. Moreover, it can be concluded that the weak acid resin carrier is completely inactive for the esterification reaction of 1-hexene, and the ratio of acetic acid to 1-hexene has a significant influence on the product selectivity. When n (acetic acid)/n (1-hexene) = 2, the optimum 1-methylpentyl acetate selectivity is 38.2%. Results of repeated experiments confirm that the stability of the active constituent is related to the type of functional groups on the carrier.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
Polymer Chemistry
·
2020
·Vol. 11
·期 14
·2492-2501
·
IF 5.342
Wenpeng Zhao,Bo Dong,Heng Liu,Yanming Hu,Xuequan Zhang
A new alternative for accessing metal–ligand containing polymers via coordination insertion copolymerization of 1-hexene and ligated α-olefin is disclosed herein. To overcome the deactivation of active species by heteroatoms, the present study employed a less electrophilic late transition metal complex, and efficient copolymerizations were successfully achieved, giving rise to poly(1-hexene) elastomers containing a benzimidazolyl quinoline ligand up to 5.77%. Moreover, the copolymerization displayed a living nature, demonstrating a capability of control over the molecular weights and molecular weight distribution. Coordination of the obtained ligated poly(1-hexene) elastomers with metal ions produced polymer networks with the ligand–metal complexes as crosslinkers and thus led to a significant enhancement of the mechanical properties of the resultant materials.
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS LETTERS
·
2022
·Vol. 153
·期 4
·1180-1192
·
IF 2.936
Xing Xiangying,Wang Huixiang,Shi Jing,Li Penghui,Ren Jingzhao,Wang Liancheng,Zhang Jianli,Liu Zhong,Lv Baoliang
WO x has good performance in olefin epoxidation, however, the presence of a large amount of Brönsted acid on WO x affects the selectivity of epoxy products. In this paper, broken carbon spheres ( b-C spheres) treated with nitric acid were used as support to anchor WO x in dynamic solvothermal process. Based on GC–MS and GC-IR detection, the obtained WO x /C greatly increased selectivity of 1,2-epoxyhexane from 16.0% ( pure WO x ) to 92.1% in epoxidation of 1-hexene. The improvement of WO x performance is attributed to the reduction of Brönsted acid sites and electron cloud density after loading, which may all result from interaction between WO x and oxygen-containing functional groups of b-C spheres. Above changes not only effectively inhibit the hydrolysis of 1,2-epoxyhexane, but also are conducive to nucleophilic reaction of H 2 O 2 to WO x, which is beneficial to the activation of H 2 O 2 . Finally, an epoxidation mechanism with oxygen vacancies as the main route under WO x /C catalysis is reasonably proposed. Graphical Abstract
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2021
·
IF 6.609
Mingjie Liao,Xin Ning,Junwen Chen,Jiajun Zheng,Wenlin Li,Ruifeng Li
Zeolite is one kind of the solid acid catalysts for the oligomerization process but surfers from rapid deactivation. In this specific study, a series of mesoporous ZSM-5 catalysts have been synthesized and evaluated in the 1-hexene oligomerization. XRD, BET, SEM, TEM, 27 Al MAS NMR, 29 Si MAS NMR, NH 3 -TPD, Py-FTIR and TGA analysis were used to characterize the physicochemical properties of zeolites. The synthesized mesoporous zeolites were found to be more stable in the reaction and the initial activity increase significantly compared with the common ZSM-5 zeolite . Moreover, the catalytic activity of mesoporous ZSM-5 zeolite is found to be closely related to the number and the distribution of acid sites. The mesoporous ZSM-5 zeolites with the lower amount of acid sites, moderate strength of Brønsted acid sites inhibiting the cracking and coke products. High L/B ratio enhanced the dimers formation. The efficiency was further highlighted by a high space–time yield (STY) of 557 mg·g cat −1 h −1 in the average stage at 260 °C. Compared to conventional ZSM-5 catalyst, the synthesized catalyst displayed excellent resistance to coke deposit.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2024
·
IF 5.3
Lei Cai,Xiu Gao,Peihang He,Beining Luo,Xianzai Yan,Zedong Zhang,Wenjun Wang,Guoqiang Wu
To improve the catalytic epoxidation activity of conventional TS-1 zeolite under acid-free conditions, a series of TS-1-supported zinc ( x Zn/TS-1) catalysts were prepared and evaluated in the epoxidation of 1-hexene and methyl oleate (MO) with H 2 O 2 oxidant. The microstructure of x Zn/TS-1 was investigated using various characterization techniques, and the results showed that the introduction of Zn species was not only well dispersed on the surface of TS-1 but also did not disrupt the crystal structure of TS-1 and tetrahedral framework titanium. Furthermore, the Ti-O-Zn structure can be formed between Zn and Ti species through O-atomic coordination, which improves the vulnerability of the Ti-O bond to attack the H 2 O 2 molecule, and ultimately facilitates the epoxidation reaction between 1-hexene and MO. In addition, the 2% Zn/TS-1 catalysts showed optimal conversions of 45.7 % and 75.41 % for 1-hexene and MO, respectively, and exhibited good catalytic stability and regeneration during the epoxidation process.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Cun Liu,Jingjing Zhang,Haiou Liu,Jieshan Qiu,Xiongfu Zhang
This work reported the heterogeneous rhodium oxide catalyst encapsulated within microporous silicalite-1 (S-1) zeolite (Rh2O3@S-1) through epitaxial growth of S-1 seeds pre-anchored with rhodium species. Based on scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) results, S-1 seeds were successfully covered by the S-1 shell and rhodium oxide was meanwhile well embedded within the zeolitic microchannel. Furthermore, a thicker S-1 shell could be modulated by secondary epitaxial growth of the as-synthesized Rh2O3@S-1 (Rh2O3@S-1-II). Those catalysts, for the first time, were applied in hydroformylation of terminal olefins, i.e., 1-hexene, 1-octene, 1-decene, and 1-dodecene, and exhibited enhanced regioselectivity compared with the supported Rh2O3/S-1 catalyst. Strikingly, with more abundant and integrated S-1 microchannels, Rh2O3@S-1-II manifested relatively the most competitive regioselectivity in the field of ligand-free rhodium nanoparticle catalysts. Experimental results and spectroscopy investigations revealed that the promoted regioselectivity was the consequence of distinctive product diffusion rates endowed by the intrinsically steric hindrance of the S-1 microchannel around the rhodium oxide.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2025
·
IF 4.3
Jiaxin Cui,Mengfan Yin,Tao Zheng,Han Liu,Rui Zhang,Haiyan Liu,Zhichang Liu,Chunming Xu,Xianghai Meng
The separation of olefins and alkanes is beneficial for resource utilization of oil products, and liquid–liquid extraction is an important method of liquid-phase olefin/alkane separation. This study investigated the feasibility of bimetallic ionic liquids for the extraction of olefin from liquid-phase olefin/alkane mixtures using 1-hexene/n-hexane as a model hydrocarbon mixture. The bimetallic ionic liquids were first synthesized from different metal chlorides (ZnCl2, SnCl2, AlCl3, FeCl3) and CuCl with triethylamine hydrochloride. This newly prepared Fe–Cu bimetallic ionic liquid [Et3NH]Cl–0.47FeCl3-0.8CuCl had a good extraction performance, and the extraction selectivity could reach up to 8.41, which was about 4 times that of the organic solvent such as N-formylmorpholine and γ-butyrolactone used in the industry. The liquid–liquid equilibrium (LLE) of 1-hexene/n-hexane and Fe–Cu bimetallic ionic liquid system was investigated under different extraction temperatures, extraction times, and mass ratios of extractant to feed. Through 5 recycling experiments, the extraction selectivity decreased by less than 2%, and the characteristic peaks of the recovered bimetallic ionic liquids were unchanged by IR analysis, which proved that the bimetallic ionic liquid had excellent reversibility. Furthermore, the mechanism of 1-hexene extraction was investigated by quantum chemistry calculation and Raman spectroscopy, and there was π-complexation between Cu+ and 1-hexene. Then, the charge density of Cu+ in bimetallic ionic liquids was larger than that of cuprous-based ionic liquids. The results revealed that the addition of FeCl3 could activate Cu+ and weaken the Cu–Cl bond, enhancing the ability of the bimetallic ionic liquid to extract 1-hexene. Therefore, [Et3NH]Cl–0.47FeCl3-0.8CuCl was a good potential extractant during the efficient extraction of 1-hexene.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）